disk: fix partition type IDs for dos

The correct partition type ID for ESP is 'ef' (not 'ef00') [1].
The partition type ID for LVM is '8e' [1].

BIOS boot partitions aren't meant for (or required) on dos partition
tables [2].  We will eventually make this a partitionless gap in the PT,
but for now let's simply use the code for 'empty'.

Use the getPartitionTypeIDfor() function for all partition type
assignments when creating partitions.

Add tests that cover all basic partition table configurations (plain,
lvm, btrfs) using dos and gpt.

[1] https://tldp.org/HOWTO/Partition-Mass-Storage-Definitions-Naming-HOWTO/x190.html
[2] https://www.gnu.org/software/grub/manual/grub/html_node/BIOS-installation.html#BIOS-installation

pkg/disk/disk.go

@@ -67,11 +67,17 @@ const (
 	// Partition type ID for any native Linux filesystem on dos
 	DosLinuxTypeID = "83"
 
-	// Partition type ID for BIOS boot partition on dos
-	DosBIOSBootID = "ef02"
+	// Partition type ID for LVM on dos
+	DosLVMTypeID = "8e"
+
+	// Partition type ID for BIOS boot partition on dos.
+	// Type ID is for 'empty'.
+	// TODO: drop this completely when we convert the bios BOOT space to a
+	// partitionless gap/offset.
+	DosBIOSBootID = "00"
 
 	// Partition type ID for ESP on dos
-	DosESPID = "ef00"
+	DosESPID = "ef"
 
 	// Partition type ID for swap
 	DosSwapID = "82"
@@ -87,7 +93,7 @@ var idMap = map[PartitionTableType]map[string]string{
 		"boot": DosLinuxTypeID,
 		"data": DosLinuxTypeID,
 		"esp":  DosESPID,
-		"lvm":  DosLinuxTypeID,
+		"lvm":  DosLVMTypeID,
 		"swap": DosSwapID,
 	},
 	PT_GPT: {

pkg/disk/partition_table.go

@@ -1275,7 +1275,9 @@ func NewCustomPartitionTable(customizations *blueprint.DiskCustomization, option
 				return nil, fmt.Errorf("%s %w", errPrefix, err)
 			}
 		case "btrfs":
-			addBtrfsPartition(pt, part)
+			if err := addBtrfsPartition(pt, part); err != nil {
+				return nil, fmt.Errorf("%s %w", errPrefix, err)
+			}
 		default:
 			return nil, fmt.Errorf("%s invalid partition type: %s", errPrefix, part.Type)
 		}
@@ -1406,8 +1408,12 @@ func addLVMPartition(pt *PartitionTable, partition blueprint.PartitionCustomizat
 	}
 
 	// create partition for volume group
+	partType, err := getPartitionTypeIDfor(pt.Type, "lvm")
+	if err != nil {
+		return fmt.Errorf("error creating lvm partition %q: %w", vgname, err)
+	}
 	newpart := Partition{
-		Type:     LVMPartitionGUID,
+		Type:     partType,
 		Size:     partition.MinSize,
 		Bootable: false,
 		Payload:  newvg,
@@ -1416,7 +1422,7 @@ func addLVMPartition(pt *PartitionTable, partition blueprint.PartitionCustomizat
 	return nil
 }
 
-func addBtrfsPartition(pt *PartitionTable, partition blueprint.PartitionCustomization) {
+func addBtrfsPartition(pt *PartitionTable, partition blueprint.PartitionCustomization) error {
 	subvols := make([]BtrfsSubvolume, len(partition.Subvolumes))
 	for idx, subvol := range partition.Subvolumes {
 		newsubvol := BtrfsSubvolume{
@@ -1431,14 +1437,19 @@ func addBtrfsPartition(pt *PartitionTable, partition blueprint.PartitionCustomiz
 	}
 
 	// create partition for btrfs volume
+	partType, err := getPartitionTypeIDfor(pt.Type, "data")
+	if err != nil {
+		return fmt.Errorf("error creating btrfs partition: %w", err)
+	}
 	newpart := Partition{
-		Type:     FilesystemDataGUID,
+		Type:     partType,
 		Bootable: false,
 		Payload:  newvol,
 		Size:     partition.MinSize,
 	}
 
 	pt.Partitions = append(pt.Partitions, newpart)
+	return nil
 }
 
 // Determine if a boot partition is needed based on the customizations. A boot